Your first 90 days on a GLP-1
Week by week: what the starter dose actually feels like, when appetite changes show up, when your provider will titrate, and the three weeks most people find hardest.
Longevity · Energy
B12 Injection
Vitamin B12 by injection for genuine deficiency, absorption problems, or long-term metformin use — not as a general energy shot.
Pricing confirmed on your consultation
Your consult is free. We will not prescribe this — or anything — before a clinician has spoken with you and reviewed your bloodwork. Final cost depends on the form and dose prescribed.
FDA-approved · Rx only
Mechanism
Only useful if you're actually low.
B12 is required for red blood cell formation, nerve function and DNA synthesis. Deficiency causes fatigue, brain fog, tingling in the hands and feet, and in prolonged cases irreversible nerve damage.
Injection bypasses the gut entirely, which matters for anyone with absorption problems, pernicious anaemia, gastric surgery, a vegan diet, or long-term metformin use.
If your levels are normal, B12 injections will not give you energy. We test rather than assume.
Protocol
How treatment usually runs.
A typical schedule. Yours is set by your clinician after your labs come back.
| Phase | Weeks | Typical | Purpose |
|---|---|---|---|
| Loading | 1–4 | Weekly injection | Where deficiency is confirmed. |
| Maintenance | 5+ | Monthly or as indicated | Guided by repeat labs. |
What to expect
Honestly, over time.
Week 1–2
Energy
Rapid response where true deficiency existed.
Week 4–8
Cognition
Brain fog and concentration typically improve.
Month 3
Recheck
Labs confirm repletion.
Ongoing
Maintenance
Frequency set by cause and labs.
Evidence
What the research shows.
B12 injection reliably and rapidly corrects confirmed deficiency, particularly where absorption is impaired.
In patients with normal B12 levels there is no evidence of an energy benefit. Testing first is the whole point.
Safety and eligibility
Your consult and labs screen for all of the following.
- Generally very safe with a wide therapeutic margin.
- Tell your provider about kidney disease or Leber's hereditary optic neuropathy.
- Common side effects are limited to injection-site reaction.
- Long-term metformin use is a common cause of deficiency and warrants monitoring.
FAQ
B12 Injection questions.
Only if you are genuinely deficient. In patients with normal levels there is no evidence of an energy benefit. That is why we test before prescribing rather than selling it as a general pick-me-up.
People with confirmed deficiency, pernicious anaemia, absorption problems after gastric surgery, strict vegan diets, and long-term metformin users, since metformin depletes B12 over time.
Typically weekly during a loading phase where deficiency is confirmed, then monthly or as your repeat labs indicate. Frequency depends on the underlying cause.
We will not prescribe before we understand you.
Book a one-to-one consult with the clinical team. We talk through your goals, order the bloodwork that matters, and build a plan from what we find.